Control of the Schottky barrier using an ultrathin interface metal layer.

Fermi level movements at Pt/GaAs and Ti/GaAs interfaces have been investigated using a direct measurement of Schottky barrier heights in a bimetal Schottky structure. Using thin interfacial layers, the Schottky barrier was smoothly varied from the characteristic value of the thick metal to that of the interfacial metal. The variation of barrier height versus the inner metal thickness was found to exhibit an exponential behavior extending over a few monolayers coverage. This experiment indicates a new approach to the fundamental study of metal-semiconductor interfaces and could be useful in device applications. [ABSTRACT FROM AUTHOR]